All this information should be in your DofE portal or from your co-ordinator. But from what I recall, you have to do your chosen activity once a week for an hour, and you have to have some way of measuring what you've achieved. So just "going for walks" to tick a box isn't what it's about, you need to set yourself a goal. I think you should check with your co-ordinator as this sounds too similar to the expedition section really. Running would be better, easier to show that you have "improved" at it.